SumoSizeit

I've got a manual 2010 JK Sport with 3.73 gears, and I'm looking to replace it with a 2013 JKU Sport. I figured I'd grab all the same options as before (same packages, trailer tow kit, etc), but this newer engine has me second guessing gear ratios. I test drove a manual JKU with 3.21 gears tonight, and I was really impressed with the performance of the Jeep. It felt much more responsive and powerful than my 2dr 3.8L with 3.73s. Up until now, I'd heard nothing but horror stories of the 3.21s, that they bog the Jeep down and make it sluggish, but it felt in every way better than my current setup.

Has the Pentastar made 3.21 gears viable, or has the wool been pulled over my eyes? I figure it's sufficient for daily driving with mild off road use and [potentially, on rare occasion] low weight towing (jet skis, maybe a Uhaul trailer), and that I'll end up changing the gears in the future anyhow if/when I finally overhaul the suspension with new axles and larger tires.

It's not that it's that expensive to get the 3.73s, but I figure there's no sense in buying what I won't use. What say you?

jadmt

If you never plan on bigger tires then 32" the 3.21 in 2012 and 2013 have plenty of giddy up but if you want to go 33's or bigger need to think about 3.73 or 4.10. I have a jku with 3.21 and 32" tires and auto which is supposed to be even better then the stick and I still wish I had 3.73 just so I could safely go to 33's or bigger.

Matthewd5

I have a 2012 jk 2 door with 33"s and 3.21's and it runs great but given the chance I'd go with 3.73's just because you can, it'll open up your options for larger tires and resale too

Matthew

Atlacatl

I have a jks 3.21's and have nothing but good things to say... Only thing I might want a different setup for is when I go to 35's... That and off road crawling is a little faster so u have to compensate for that...

TheTerminator

The new engine has more power, which means it can run taller gears better. If you never going to upgrade your tires, then 3.21 would be fine. But if you will, then why not go with 3.71? This will save you from regearing down the road to 4.10 or 4.56. It most likely won't be worth it and difference will be just slight. With 3.21 the difference becomes larger. If you're going to replace axles as you said, then I guess 3.21 will do fine. 3.71 will help more on the trail though, if you even need low gearing.

SumoSizeit

I figure if I reach the point where I'm considering 4.10/4.56, I'll need stronger axles than stock. 35s or 37s would be nice, but below that I'm not sure it's a good return on investment over stock 32s.

07tungsten

I'm happy with the 3.21s on my 2013. I had an 08 previously and I would have wanted the 3.73 but this new engine is much better. But ask me next week when I get my 33" tires lol!

I will say I knowingly ordered these gears hoping I would get a bit better gas mileage.

TheTerminator

Upto 35's you should be fine on stock axles. Some even wheel on 37's and stock axles. And even then, you'd need to get into the hard stuff to break them. Some logging roads and a few flexes here and there won't hurt the axles.

Canibeat

Is it worth the money to regear, running 33's on 3.73 a good ideal? I need new tires soon don't know if it would a signification difference and beneficial to spend some hard earn money on gears. Thanks!

CliffCrawler

I had a 3.21s in my 2 door 07. Drive great for the first 3 months and sluggish. Then my 2008 4 door with 35s in 3.21s, and great for daily rides and awesome to offload. The my 2010 4 door with 3.73s and no difference noticed with stadard bfgs. Now my 2012 rubi and yes, the engine is great but after a while its all the same.... Truth I learned after seeking a perfect JK, I should have stopped on the 2008 and continued to perfect... By now it would have been paid off, I would have had 400$ bucks a month to play with, lifetime warranty and most of all, not all the new gadgets that sometimes causes more issues. Bottom line, 3.21 vs 3.73..... Go for the best deal, drive down the price, ask for free crap in the deal like oil changes... It's all perspective.